Final answer:
DNA polymerase III is the primary enzyme responsible for genome replication in E. coli, playing a key role in adding nucleotides to the growing DNA chain.
Step-by-step explanation:
The DNA polymerase mainly responsible for genome replication in E. coli is DNA polymerase III. This enzyme is crucial for the synthesis of DNA, as it adds deoxyribonucleotides to the growing DNA chain that are complementary to the template strand. DNA polymerase I and DNA polymerase II have roles primarily in repair functions within the cell. The replication process requires energy provided by triphosphate nucleotides, similar to ATP, to form the necessary phosphodiester bonds between nucleotides.